That figure is still well short of the $288,000 in expenses the treasurer, an office worker at the law firm of noted Republican activist Richard McLellan, reported spending on the ad buy and consulting services with Sterling Corporation. The $100,000 shortfall could have been covered in the 10 days between the July 13 report and the amended report.

But questions about the group went unanswered after those behind the Super PAC did not return calls for comment.

Major donors include a $62,500 contribution from Dan Carroll, a vice president at an energy company and a supporter of the Durant-founded Cornerstone Schools, and $25,000 each from JM Jung and Robert Thompson. Patrick Kerzic and Robert Liggett Jr. each put in $15,000, records show.

All told, documents reveal, 11 donors ponied up varying amounts to the political action committee that has a murky background. The committee registered in March, but its website shows only its name and offers no information about the group or its intentions.

Federal records show it organized to support Durant in the GOP race that also includes former Kent County Probate Judge Randy Hekman.

The PAC’s treasurer, Jennifer Satterlee, is an employee at McLellan’s Lansing law office. She said McLellan had no affiliation with the group but wouldn’t explain how she and the assistant treasurer, an intern at McLellan’s firm, became involved. McLellan’s office and the committee’s registered address are on the same floor of an office building near the state capitol.

McLellan has been active in campaign finance lawsuits, including filing a brief in the Citizens United case that led to the U.S. Supreme Court’s 2010 decision that opened up campaigns to unlimited cash from corporations.

The Lansing lawyer also was involved in the 1990 state Supreme Court case that pitted then-Michigan Secretary of State Richard Austin against the Michigan Chamber of Commerce. The court ruled against corporate donations for independent candidate expenditures, the decision that was overturned in Citizens United.

McLellan was positioned with the chamber, which at the time had Robert LaBrant on staff as its political and legal counsel. LaBrant is now senior counsel at the Sterling Corporation.

The commercial from Prosperity for Michigan alleges Hoekstra’s votes as a nine-term Congressman resulted in “billions in earmarks, raising his own pay, adding trillions to the debt and raising the debt ceiling.”